NPL's commercial services are built on 100 years of leadership in accuracy, innovation and scientific research. Experienced consultants and project managers draw upon a unique combination of industry know-how and world-leading scientific discovery to deliver real-world business solutions and enable innovation and secure competitive advantage.

We strive to actively promote public awareness and appreciation of science and technology, particularly the importance of measurement and the role of NPL. Here you can find out more about the interesting things we do, science outreach activities you can get involved in or take a look at some of our educational resources.

Measurement of therapeutic ultrasound fields

Hydrophone field mapping facility

NPL Acoustics offers wide ranging and traceable measurement, R&D, design and consultancy services for medical ultrasound in the range 0.7 to 40 MHz. We have the capability and facilities to characterise complex devices such as multi-element phased arrays used for high intensity therapeutic ultrasound (HITU or HIFU). Using our range of unique measurement tools we can provide a complete solution for manufacturers, developers and users of therapeutic ultrasound equipment.

Hydrophone field mapping

We perform field measurements in a dedicated scanning tank using a range of membrane, needle and fibre optic hydrophones. Special acoustic attenuators allow us to characterise transducers driven at clinical levels.(IEC 62127, IEC 61689, IEC 62556)

Acoustic power measurement using the buoyancy change method

Acoustic power

We measure acoustic output powers from 5 mW up to at least 500 W by radiation force and by the NPL buoyancy change method developed for strongly focused fields. We can also measure electrical power into transducers in real time to calculate transducer efficiency.(IEC 61161 and IEC 62555)

Thermal field mapping

Our thermal imaging system rapidly scans complex acoustic fields in 3-D, to map the intensity distribution by measuring the heating pattern produced in a thin absorber.

Composite thermal image of the field of a multi-element phased array showing six focal points